scholarly journals Isogeometric finite element‐based simulation of the aortic heart valve: Integration of neural network structural material model and structural tensor fiber architecture representations

2021 ◽  
Author(s):  
Wenbo Zhang ◽  
Giovanni Rossini ◽  
David Kamensky ◽  
Tan Bui‐Thanh ◽  
Michael S. Sacks
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Structural Material ◽  
Heart Valve ◽  
Material Model ◽  
Fiber Architecture ◽  
Structural Tensor ◽  
Aortic Heart Valve

Investigation of the tubular leaflet geometry of an aortic heart valve prosthesis by finite-element analysis

BIOPHYSICS ◽  
2015 ◽  
Vol 60 (5) ◽  
pp. 827-834 ◽  
Author(s):  
E. A. Ovcharenko ◽  
K. Yu. Klyshnikov ◽  
D. V. Nushtaev ◽  
G. V. Savrasov ◽  
L. S. Barbarash
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heart Valve ◽  
Heart Valve Prosthesis ◽  
Valve Prosthesis ◽  
Element Analysis ◽  
Aortic Heart Valve

Design and simulation of a poly(vinyl alcohol)—bacterial cellulose nanocomposite mechanical aortic heart valve prosthesis

2009 ◽  
Vol 223 (6) ◽  
pp. 697-711 ◽  
Author(s):  
H Mohammadi ◽  
D Boughner ◽  
L E Millon ◽  
W K Wan
Keyword(s):  
Bacterial Cellulose ◽  
Heart Valve ◽  
Vinyl Alcohol ◽  
Soft Tissues ◽  
Material Model ◽  
Poly Vinyl Alcohol ◽  
Valve Prosthesis ◽  
Aortic Heart Valve ◽  
Non Linear ◽  
Mechanical Models

In this study, a polymeric aortic heart valve made of poly(vinyl alcohol) (PVA)—bacterial cellulose (BC) nanocomposite is simulated and designed using a hyperelastic non-linear anisotropic material model. A novel nanocomposite biomaterial combination of 15 wt % PVA and 0.5 wt % BC is developed in this study. The mechanical properties of the synthesized PVA—BC are similar to those of the porcine heart valve in both the principal directions. To design the geometry of the leaflets an advance surfacing technique is employed. A Galerkin-based non-linear finite element method is applied to analyse the mechanical behaviour of the leaflet in the closing and opening phases under physiological conditions. The model used in this study can be implemented in mechanical models for any soft tissues such as articular cartilage, tendon, and ligament.

A Multiscale Finite Element Simulation of Human Aortic Heart Valve

2013 ◽  
Vol 367 ◽  
pp. 275-279
Author(s):  
Shahrokh Shahi ◽  
Soheil Mohammadi
Keyword(s):  
Finite Element ◽  
Heart Valve ◽  
Heart Valves ◽  
Cellular Level ◽  
Aortic Heart Valve ◽  
Multiscale Finite Element ◽  
Local Cell ◽  
Scale Motion ◽  
Human Aortic Valve ◽  
Tissue Engineered Heart Valves

Some of the heart valve diseases can be treated by surgical replacement with either a mechanical or bioprosthetic heart valve (BHV). Recently, tissue-engineered heart valves (TEHVs) have been proposed to be the ultimate solution for treating valvular heart disease. In order to improve the durability and design of artificial heart valves, recent studies have focused on quantifying the biomechanical interaction between the organ, tissue, and cellular –level components in native heart valves. Such data is considered fundamental to designing improved BHVs. Mechanical communication from the larger scales affects active biomechanical processes. For instance any organ-scale motion deforms the tissue, which in turn deforms the interstitial cells (ICs). Therefore, a multiscale solution is required to study the behavior of human aortic valve and to predict local cell deformations. The proposed multiscale finite element approach takes into account large deformations and nonlinear anisotropic hyperelastic material models. In this simulation, the organ scale motion is computed, from which the tissue scale deformation will be extracted. Similarly, the tissue deformation will be transformed into the cell scale. Finally, each simulation is verified against a number of experimental measures.

Transcatheter aortic heart valve (THV) implantation of Edwards Sapien™ bioprothesis – using a mobile x-ray-system or a hybrid-OR?

2010 ◽  
Vol 58 (S 01) ◽  
Author(s):  
H Schröfel ◽  
G Schymik ◽  
A Würth ◽  
V Elsner ◽  
BD Gonska ◽  
...  
Keyword(s):  
Heart Valve ◽  
X Ray ◽  
Aortic Heart Valve ◽  
Edwards Sapien

Delamination in the scoring and folding of paperboard

TAPPI Journal ◽  
2012 ◽  
Vol 11 (1) ◽  
pp. 61-66 ◽  
Author(s):  
DOEUNG D. CHOI ◽  
SERGIY A. LAVRYKOV ◽  
BANDARU V. RAMARAO
Keyword(s):  
Finite Element ◽  
Plane Deformation ◽  
Strain Analysis ◽  
Local Strain ◽  
Uniaxial Stress ◽  
Material Model ◽  
Element Model ◽  
Plastic Behavior ◽  
Stress Strain ◽  
Strain Fields

Delamination between layers occurs during the creasing and subsequent folding of paperboard. Delamination is necessary to provide some stiffness properties, but excessive or uncontrolled delamination can weaken the fold, and therefore needs to be controlled. An understanding of the mechanics of delamination is predicated upon the availability of reliable and properly calibrated simulation tools to predict experimental observations. This paper describes a finite element simulation of paper mechanics applied to the scoring and folding of multi-ply carton board. Our goal was to provide an understanding of the mechanics of these operations and the proper models of elastic and plastic behavior of the material that enable us to simulate the deformation and delamination behavior. Our material model accounted for plasticity and sheet anisotropy in the in-plane and z-direction (ZD) dimensions. We used different ZD stress-strain curves during loading and unloading. Material parameters for in-plane deformation were obtained by fitting uniaxial stress-strain data to Ramberg-Osgood plasticity models and the ZD deformation was modeled using a modified power law. Two-dimensional strain fields resulting from loading board typical of a scoring operation were calculated. The strain field was symmetric in the initial stages, but increasing deformation led to asymmetry and heterogeneity. These regions were precursors to delamination and failure. Delamination of the layers occurred in regions of significant shear strain and resulted primarily from the development of large plastic strains. The model predictions were confirmed by experimental observation of the local strain fields using visual microscopy and linear image strain analysis. The finite element model predicted sheet delamination matching the patterns and effects that were observed in experiments.

Lifetime Prediction of Tires with Regard to Oxidative Aging5

2008 ◽  
Vol 36 (1) ◽  
pp. 63-79 ◽  
Author(s):  
L. Nasdala ◽  
Y. Wei ◽  
H. Rothert ◽  
M. Kaliske
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Superposition Principle ◽  
Accelerated Aging ◽  
Material Model ◽  
Aging Behavior ◽  
Element Analysis ◽  
Material Parameters ◽  
Reaction Processes

Abstract It is a challenging task in the design of automobile tires to predict lifetime and performance on the basis of numerical simulations. Several factors have to be taken into account to correctly estimate the aging behavior. This paper focuses on oxygen reaction processes which, apart from mechanical and thermal aspects, effect the tire durability. The material parameters needed to describe the temperature-dependent oxygen diffusion and reaction processes are derived by means of the time–temperature–superposition principle from modulus profiling tests. These experiments are designed to examine the diffusion-limited oxidation (DLO) effect which occurs when accelerated aging tests are performed. For the cord-reinforced rubber composites, homogenization techniques are adopted to obtain effective material parameters (diffusivities and reaction constants). The selection and arrangement of rubber components influence the temperature distribution and the oxygen penetration depth which impact tire durability. The goal of this paper is to establish a finite element analysis based criterion to predict lifetime with respect to oxidative aging. The finite element analysis is carried out in three stages. First the heat generation rate distribution is calculated using a viscoelastic material model. Then the temperature distribution can be determined. In the third step we evaluate the oxygen distribution or rather the oxygen consumption rate, which is a measure for the tire lifetime. Thus, the aging behavior of different kinds of tires can be compared. Numerical examples show how diffusivities, reaction coefficients, and temperature influence the durability of different tire parts. It is found that due to the DLO effect, some interior parts may age slower even if the temperature is increased.

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